Labcoat crashes when trying to add an issue on Android 4.3

When I press the plus-button to add an issue the app id closed immediately.

The relevant part of catlogs output shows:
2017-05-27 04:34:59,ERROR,AndroidRuntime,Unknown,FATAL EXCEPTION: main
java.lang.NoClassDefFoundError: com.commit451.morphtransitions.FabTransform
at com.commit451.gitlab.activity.MorphActivity.morph(MorphActivity.kt:17)
at com.commit451.gitlab.activity.AddIssueActivity.onCreate(AddIssueActivity.kt:97)
at android.app.Activity.performCreate(Activity.java:5372)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1104)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2257)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2349)
at android.app.ActivityThread.access$700(ActivityThread.java:159)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1316)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5419)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1187)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
at dalvik.system.NativeStart.main(Native Method)